I thought I'll just search around in the Xbox forums for these infos, it worked out well enough.

There's not much new they have talked about, putting up the points from this guy's post...

- You can store stuffs in the trunks of cars.
- Cars are now more realistic, suspension will react to the streets below and more realistic damage modeling.
- Jacking a locked car is a one-button job but shows him putting an elbow through the window and hotwiring it.
- You can hear radios from other cars.
- Target system appeared to be a free-look model, similar to Saints Row, but R* hasn't confirmed anything about it.
- Seagulls, Cigaretes, Cell phones are all ambient.